1. Field of the Invention
The present invention relates to a linear transport device which uses a linear motor as its drive source.
2. Description of the Related Art
A linear transport device of this type is provided with a base, rails that are laid on the base, and a platform car that moves on and along the rails. In order to drive the platform car, a linear motor has been conventionally used as the drive source. A well-known linear motor is provided with a stator fixed to the foregoing base, and a mover fixed to the platform car. With respect to the stator and the mover, one is a permanent magnet and the other is an electromagnet. By controlling current supply to the coil of the electromagnet, the propulsion is generated to the platform car based on the mutual effect of the magnetic flux between the stator and the mover.
The platform car is configured such that it is mounted on the rails and is only allowed to move in the longitudinal direction thereof. Accordingly, during maintenance, standard practice is to move the platform car to the device end and remove the platform car by pulling the platform car in the longitudinal direction from the rail end.
For example, Japanese unexamined Patent Application No. 2001-341841 discloses a linear transport device in which a part of the base is adapted to be slidable in the width direction together with the rails and the stator. In this prior art, by sliding the platform car together with a part of the base, the platform car can be removed at a portion that is midway in its range of motion.
In order to pull out the platform car in the foregoing conventional linear transport device, space is required around the device on the surface to which the base is mounted. If it is not possible to have sufficient space around the device, it will be detrimental to the removal of the platform car. Moreover, with types where the platform car is pulled out from the rail end, a disassembly operation of removing parts such as a stopper that is fixed to the rail terminal part is required.
Accordingly, what is required is a linear transport device with favorable maintenance performance which is capable of easily removing the platform car with fewer processes without having wide space around the device.